President Barack Obama may be just about done with this Congress, but there’s one thing he can’t do without — money.

Before Congress adjourns in a month for the August recess, Obama wants lawmakers to pass a supplemental spending bill dealing primarily with the child migrant crisis , while also averting a slowdown of highway projects.

And after the break, Congress will have to agree on a spending bill to avoid a pre-election government shutdown — with Obama pushing Congress for a host of controversial items, including $500 million for Syrian rebels, a new anti-terrorism foreign aid fund and the authority to close the military prison in Guantánamo Bay, Cuba.

The bottom line: While Obama has used his pen and phone to enact a host of administrative changes this year, he can’t pen and phone his way around Congress’ power of the purse. White House Press Secretary Josh Earnest told reporters the administration would detail its supplemental spending request Tuesday and said the measure would include a surge of personnel to adjudicate border migrant cases and other items.

Earnest has expressed hope that Congress could act quickly to provide both the funding and new authorities for Homeland Security Secretary Jeh Johnson so the administration can quickly process and, in most cases, deport the children to their home countries in Central America.

It’s not clear yet whether Congress would approve anything — or if the White House will have to swallow any riders or offsetting budget cuts Republicans might demand in return. GOP aides held their fire Monday ahead of the official request.

"We should tell these countries in Central America that no more aid, no more assistance, no nothing until they stop this from happening,” the Arizona Republican told KFYI radio in Phoenix. “And tell our friends in Mexico to secure their border, their Southern border as well as their Northern border, and no comprehensive immigration reform until we get our border secured. It’s unacceptable."

Other Republicans have blamed the border crisis, in part, on the president’s decision to unilaterally grant deportation relief to many immigrants brought to the United States as children.

The House already has voted to defund that program, known as DACA, and some Republicans recently wrote to Obama demanding he immediately end the program.

The White House has strongly rejected the GOP argument, and with chances of an immigration overhaul dead for the year , Obama is looking to expand deportation relief on his own, not shrink it — even as the administration emphasizes changes would not apply to new immigrants.

It's all rubbing Republicans the wrong way.

"In the same breath, at that moment when he asked for more money to take care of the crisis, he announced that he would deliberately and openly go around the Congress of the United States and the Constitution and unilaterally change immigration law again through an enforcement policy," Sen. Jeff Sessions, R-Ala., said Monday on the floor.

But even Sessions suggested Congress will need to find some money to deal with the crisis.

"We've got to take care of the children. We can't leave them in a circumstance where they're not fed or taken care of or in safe condition. We'll have to find some money, I guess, to do that. But the question is: how did it happen? Why did it happen?”

Sessions also told CQ Roll Call any new spending should be offset: “I don’t think the president should be rewarded for his failures by just having us borrow more money to just pay for that.”

Sessions suggested raising $4.2 billion to fund the program by making it harder for people in the country illegally to claim the Additional Child Tax Credit. His proposal would require a Social Security number to claim the benefit, cutting out those who have U.S. citizen children but aren't authorized to be here.

Sen. Richard C. Shelby, R-Ala., the ranking member on appropriations, said of the request "absolutely it ought to be offset." He suggested starting with rescissions from the Affordable Care Act.

Sessions called the president's position a "disconnect," noting he views it as "ironic that he demands Congress provide him money while the money he’s demanding is needed because of his failure to enforce congressionally passed law."

Sessions suggested House Republicans could attach to Obama's funding request conditions that would require the administration to enforce current immigration law to access the funds.

The supplemental request will get a hearing Thursday in the Senate Appropriations Committee.

Then there’s the potential for a September shutdown showdown. Republican leaders haven’t shown any appetite for a reprise of last year’s partial government closure drama, which ended when the GOP capitulated on demands to defund Obamacare.

As he cranks into action ahead of the Nov. 4 midterm elections, Obama has been increasingly dismissive of the Capitol’s dysfunction, blaming Republican partisan politics while saying he’s ready to work with the GOP if they're willing to work with him.

But his relationship with Speaker John A. Boehner of Ohio is at a low point, given the House GOP lawsuit and the speaker's refusal to bring an immigration bill to the floor. The president brushed off the lawsuit threat with a “so sue me” line, and also has dismissed the idea that golfing more with Boehner would accomplish anything.